What are the typical certification I should have to be a travel RN?

You need experience working as a nurse most importantly. Certification in your area of specialty would be a bonus.

It depends on what specialty you want to travel as. Just med/surg or Telemetry you don't need certifications, other than BLS and ACLS.

I’ve never traveled but a PCCN would certainly give you a leg up. Multiple options available.