Oracle 21c

DECLARE
    FUNCTION getBase64Encoded(tnc IN VARCHAR2)
        RETURN CLOB
        IS
        encodedTnC CLOB;
    BEGIN
        encodedTnC := TO_CLOB(utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(tnc))));

RETURN encodedTnC;
    END;

INSERT_STATEMENT  VARCHAR2(10000) := 'INSERT INTO SOME_TABLE ' ||
                                         '(PRODUCT_ID, ENCODED_TEXT) ' ||
                                         'VALUES (:1, :2)';
    encodedTextForProd1 VARCHAR2(10000) := getBase64Encoded('some plain text here');
    encodedTextForProd2 VARCHAR2(10000) := getBase64Encoded('some plain text here again');

BEGIN

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd1;

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd2;

COMMIT;

EXCEPTION
    WHEN OTHERS THEN
        ROLLBACK;
END;
/

ORA-06550: line 12, column 5:
PLS-00103: Encountered the symbol "INSERT_STATEMENT" when expecting one of the following:

   begin function pragma procedure

DECLARE
    INSERT_STATEMENT  VARCHAR2(10000) := 'INSERT INTO SOME_TABLE ' ||
                                         '(PRODUCT_ID, ENCODED_TEXT) ' ||
                                         'VALUES (:1, :2)';
    encodedTextForProd1 VARCHAR2(10000) := getBase64Encoded('some plain text here');
    encodedTextForProd2 VARCHAR2(10000) := getBase64Encoded('some plain text here again');

FUNCTION getBase64Encoded(tnc IN VARCHAR2)
        RETURN CLOB
        IS
        encodedTnC CLOB;
    BEGIN
        encodedTnC := TO_CLOB(utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(tnc))));

RETURN encodedTnC;
    END;

BEGIN

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd1;

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd2;

COMMIT;

EXCEPTION
    WHEN OTHERS THEN
        ROLLBACK;
END;
/

ORA-06550: line 5, column 44:
PLS-00313: 'GETBASE64ENCODED' not declared in this scope
ORA-06550: line 0, column 0:
PL/SQL: Compilation unit analysis terminated

DECLARE
    INSERT_STATEMENT  VARCHAR2(10000) := 'INSERT INTO SOME_TABLE ' ||
                                         '(PRODUCT_ID, ENCODED_TEXT) ' ||
                                         'VALUES (:1, :2)';
    encodedTextForProd1 VARCHAR2(10000);
    encodedTextForProd2 VARCHAR2(10000);

FUNCTION getBase64Encoded(tnc IN VARCHAR2)
        RETURN CLOB
        IS
        encodedTnC CLOB;
    BEGIN
        encodedTnC := TO_CLOB(utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(tnc))));

RETURN encodedTnC;
    END;

BEGIN

encodedTextForProd1 := getBase64Encoded('some plain text here');
    encodedTextForProd2 := getBase64Encoded('some plain text here again');

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd1;

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd2;

dbms_output.put_line(encodedTextForProd1);
    dbms_output.put_line(encodedTextForProd2);

COMMIT;

EXCEPTION
    WHEN OTHERS THEN
        ROLLBACK;
END;
/

1 rows affected

dbms_output:
c29tZSBwbGFpbiB0ZXh0IGhlcmU=
c29tZSBwbGFpbiB0ZXh0IGhlcmUgYWdhaW4=

DECLARE
    FUNCTION getBase64Encoded(tnc IN VARCHAR2)
        RETURN CLOB;

INSERT_STATEMENT  VARCHAR2(10000) := 'INSERT INTO SOME_TABLE ' ||
                                         '(PRODUCT_ID, ENCODED_TEXT) ' ||
                                         'VALUES (:1, :2)';
    encodedTextForProd1 VARCHAR2(10000) := getBase64Encoded('some plain text here');
    encodedTextForProd2 VARCHAR2(10000) := getBase64Encoded('some plain text here again');

FUNCTION getBase64Encoded(tnc IN VARCHAR2)
        RETURN CLOB
        IS
        encodedTnC CLOB;
    BEGIN
        encodedTnC := TO_CLOB(utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(tnc))));

RETURN encodedTnC;
    END;

BEGIN

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd1;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd1;

--EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to X company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Y company', encodedTextForProd2;
    --EXECUTE IMMEDIATE INSERT_STATEMENT USING 'productId when sold to Z company', encodedTextForProd2;

dbms_output.put_line(encodedTextForProd1);
    dbms_output.put_line(encodedTextForProd2);

COMMIT;

EXCEPTION
    WHEN OTHERS THEN
        ROLLBACK;
END;
/

1 rows affected

dbms_output:
c29tZSBwbGFpbiB0ZXh0IGhlcmU=
c29tZSBwbGFpbiB0ZXh0IGhlcmUgYWdhaW4=