If you have funds stored on a paper wallet and you want to spend from that safely you can do so with Electrum without exposing your private key to an online computer:
- You will need an offline computer and an online computer.
- You will need to install Electrum on both the offline and online systems.
- On the online system create a non-deterministic watch-only wallet with the address of the paper wallet.
- On the offline system create an imported private key wallet using the paper wallet’s private key.
- On the online system go to the send tab and enter the payee’s details and the amount you want to send them. Click on preview to view the unsigned transaction. Click on export to save it to a removable drive.
- On the offline system go to tools menu > load transaction > from file and load the unsigned transaction. Click on sign and then export the signed transaction back to the removable drive.
- On the online system load the signed transaction using tools menu > load transaction > from file and click on broadcast.
Electrum will send change, if any, back to the paper wallet’s address so keep the paper wallet safe.
If you are going to be spending from cold storage a lot you might consider creating a deterministic cold wallet setup. See here for instructions on how to create such a setup.