Apologies for delay on this - got attacked by work so just getting some spare time now.
TPWD boat forms page - https://tpwd.texas.gov/regulations/outdoor-annual/boating/boating-references-tools-forms
So to start registering your kayak - you can look at the following chart that TPWD provides to cover basically all scenarios - to see what paperwork you need to title/register (you have to be titled to be registered)
Registration & Titling - https://tpwd.texas.gov/fishboat/boa...and-or%20Registered%20Through%20TPWD.pdf
For your scenario (and mine) - it is a used kayak that has never been registered - so we need the following forms documents
1) Vessel/Boat Application (PWD 143)
2) Verification of Vessel Serial Number (PWD 504)
3) Bill of Sale. Basically page listing the price you paid for the kayak - for tax purposes. Ideally signed by you and the seller. Also helps to have a bank/app transaction for evidence as well (zelle/vinmo)
4) Affidavit of Fact (why was this not registered prior) - its a kayak - prior owner chose not to put a motor on it... I plan to
5) MSO (manufactures statement of orgin) - request from prior owner OR reach out to manufacturer.
You will need to pay the following
1) title fee
2) registration fee
3) tax on sale
That should cover you for everything!