What is the best, easy and least cost to transfer my 2 condo in Bangkok to my daughter and her mom (not married)

You need to be more specific.

Are your intended beneficiaries Thai citizens?

When do you wish to transfer-immediate future or upon your demise?

Ball park values of the properties.

Why are you transferring?

Who is the mom 'not married 'to.

You need to be more specific.

Are your intended beneficiaries Thai citizens?

When do you wish to transfer-immediate future or upon your demise?

Ball park values of the properties.

Why are you transferring?

Who is the mom 'not married 'to.

Here is more info; they are both Thai citizen. not married to mom but leaving together for few years, vale are about 3 million bth, just want to make sure they own the property if something happen to me, and transfer right away

If you transfer in the regular way then government transfer costs will be incurred.

There are many posts on this forum dealing with these costs.
You do not need a lawyer or any other professional.

Your local Land office will advise the details
Assuming that the condos are in your name you will require certificates to prove that

the condos are debt free. The condo management will provide this-maybe for a fee.

If ,on the other hand ,you organise a Will leaving the properties to mom (or to the

daughter if mom dies first) then transfer costs are much reduced or possibly
eliminated.

As delight stated..get a will..no costs on inheritance..if you want to transfer now cost based on land department appraisal..probably 2-300k combined for fees as you will absorb all of them.

A will is the best option as you can also change it, if things go wrong..transferring now makes no sense.