Can I partially apply for my Thai visa while in Thailand and complete it later from Vietnam?

Dear Friends,

I’m currently in Bangkok. I will apply my dtv from Vietnam at the end of this month.

I would like to know that;

Can I start apply on application partially now and get ready during inside Thailand ? then, When I reach Vietnam I will add the rest of information. After that summit.

I’m abit worry if this is break the rule or it is ok to do that. It show that to apply when we are outside of Thailand.

Can someone suggest me, please.

Thank you very much.