It generally takes 2-3 weeks. TREC cannot finish processing your application until you have sent TREC all of your certificates and they have received them all. You will get a notification from them via email if you have been accepted or rejected. If you are accepted, you will get an “Eligibility Letter” from TREC, containing your TREC ID number and your next steps.
You can also check TREC's processing times on TREC's website!
Delays can be caused by missing information or by TREC simply not receiving your application in the mail. If you applied via mail, TREC will reach out to you. If you applied online, TREC will not reach out to you; your application will simply sit in their online database until you check in with TREC about your status. This is why it’s extremely important to fill everything out as completely as possible and include all required documentation!