I sent some btc to Electrum but I didn't enter the number, the address was generated and I used it but now I only see "not confirmed" in red in my wallet. Can you advise me how to confirm the transaction so I don't have it in red? thx
You should create your own thread about this since it is off topic here.
The transaction will be unconfirmed because the fee is too low for it to have been included in a block yet. Depending on the fee and the specifics of the transaction your options are either to wait longer, or to use either RBF or CPFP to bump the fee.
RBF is the better option for bumping the fee, but whether or not you can use it depends on where you sent the bitcoin from and whether the transaction is opted in to RBF. You can easily use CPFP by spending the unconfirmed bitcoin in a new transaction back to yourself with a much higher fee, but this is obviously going to be very costly.
If you are happy to share your transaction ID, I can take a closer look for you.