Hi @ikubra800. The data types for each format is based on the specific format. PostgreSQL supports the "serial" data type, where Oracle doesn't, therefore it isn't available in the Oracle Writer. Hope that makes sense.
I see from your screenshot above that you had SEQ_ID datatype set to "number." If you're using the UUID() function in the text editor from the writer feature type as shown below, ensure you have set a Data Type that supports the UUID values (i.e. clob).
If the UUID() function doesn't work for some other reason, try adding the UUIDGenerator transformer prior to writing and set the "New UUID Attribute" to SEQ_ID.
@ikubra800 Just for completeness... Oracle sequences are analogous to the postgres serial data type.
The sequence must be an integer data type on the Oracle writer. It can also be the primary key. To use a sequence you can set the Sequenced Table Columns parameter on the Oracle Writer Feature Type Advanced disclosure group: