Taking additional exams without company needing them

Hello all,

I work as a stockbroker for a small brokerage firm. My firm helped me get Series 7 and 63. Although my company doesn't need me to take any additional exams, I thirst for more knowledge. I want to take Series 3, 65, and 67 to add more qualifications to my resume (and perhaps switch to another firm in the future).

I already have a U4. Can I go register for the exams myself or does my company have to do it for me? I don't know the process. When I took 7 and 63, my company opened an exam window for me, then I went to FINRA's website to choose exam dates. I don't remember seeing any payment option on the website since my company paid for me.

I appreciate your answers!