The import/export specs are saved in the system tables MSysIMEXSpecs and MSysIMEXColumns.  You need to enable the "show hidden and system objects" options of the navigation pane to see them.  MSysIMEXSpecs stores the spec names, delimiters, separators, etc.  MSysIMEXColumns stores info about the field names in the specs.  Needless to say, you need to backup your database before you do anything with hidden system tables.

Thank you Kevin.
Unfortunately, this does not tell me enough on how to edit and understand what is doing. Would you have a link to this topic that i can maybe try out and understand how to edit what is doing. Btw thanks for the prompt reply.

You edit those tables the same way you edit any other tables -- manually, and/or with action queries, and/or with VBA.  If you are unfamiliar with those topics, you need to learn them, such as with the courses on this site.  They are pretty big topics (and important and fundamental too), and can't be covered with one or two posts here.  

The structures of those tables are pretty self-explanatory: Spec Name and SpecID identify the individual specs; delimiters, separators, etc. have their own fields.  To change a delimiter from "," to ";", you just go to the proper field in the table and change it.  To see how a "Tab" delimiter is stored in the table, create a spec with a Tab delimiter, then see what it looks like in the table.

Again, since you are dealing with hidden system tables, you also need the added caution that any mishap could possibly corrupt the database.

Also, these tables are hidden for a reason: only advanced and knowledgeable users should handle them.  You likely won't find "tutorials" for this kind of thing because this is not something an average user should do.