What is op::transfer() in jetton wallet smart contract?
It gives me an error when I want to send this kind of op.

More information is needed to understand what your problem is. What kind of error? What other data are you sending? Also see the standard https://github.com/ton-blockchain/TEPs/blob/master/text/0074-jettons-standard.md

I want to send a jetton to some address in my smart contract so I shoud send a message to contract's jetton wallet with a transfer operation. Like this:
store_uint(op::transfer(), 32)
But Blueprint says undefined function 'op::transfer'

That's because op::transfer() is just not defined in your code. Copy it from op-codes.fc file from token-contract repo

BTW that picture was useful for me can you send it again.

https://github.com/ton-blockchain/token-contract/blob/991bdb4925653c51b0b53ab212c53143f71f5476/ft/op-codes.fc#LL1

Which picture?

It has just deleted.
It says after operation what should we put in our msg cell.

This is a screenshot from TEP74 🙂
https://github.com/ton-blockchain/TEPs/blob/master/text/0074-jettons-standard.md