- Go to Settings > Messages > Encryption.
- Tick the box Sign all my emails with my personal key.
Make sure you have the OpenPGP key pair/Personal key of all sender addresses.
Mailfence does not allow signing emails from revoked/expired OpenPGP key pairs/Personal keys.
The recipient will need to have your OpenPGP public key to be able to validate your digital signature. You can share your OpenPGP public key by email.