Hi Kat,
Yes, you are able to import custom fields. During the import process, you can specify to create a new field for a specific column. For example, if in the import file you have a header called ‘ContactRegion’, then during the import process, the import tool will allow you to create a new a field for ‘ContactRegion’.
However, in terms of ‘Job Title’, the Contact table already contains a field named 'Title' which is used for the same purpose.
Furthermore, a brief summary of the standard import process can be found here.