I made a transaction on a watch only wallet on Android using electrum v4.4.5.0.
When I tried to export the transaction as a QR code I got the following message.
"Warning: Some data (prev txs / "full utxos") was left out of the QR code as it would not fit. This might cause issues if signing offline. As a workaround, try exporting the tx as file or text instead."
Now, there is no option on android electrictrum to save as a file. I can copy the text and put it in a txt file but what should I name the extention and will it work if imported as a file.
This slows the process right down, so hopefully a fix on the scanner or at the very least an option to save the transaction in file format. I have submitted a bug report on GitHub.
I have not used Mobile version for a transaction to send coins but just checked the basic feature after reading your topic.
Let's have the transaction copied from the wallet and it's in your clipboard now.
Open the wallet, click send, click the paste button (icon).
In the next window you will see two buttons. Since my one is a multi signature wallet, it is showing me Share button on the left bottom. I am assuming if I was the (n-1)th signer then it would show send/sign button and finally would allow me to broadcast the transaction.
If you are copying/saving a file, I don't think you need an extension for it. The software will do its own job.