The fact of sending funds is the presence of the so-called “Transaction hash” (this can be considered the transaction ID).

This identifier must be requested in a search on the blockchain scanner website (every blockchain has one).

There will be data reflecting the number of confirmations (number of blocks in a blockchain the transaction was added to) in the transaction information. If there are many blocks (at least more than 5), it can be assumed that the transaction has reached the receiver and cannot be canceled.