If you choose to forgive but cannot reconcile (because the other remains dangerous), then you can offer forgiveness without even saying directly to the other, “I forgive you.” You can give to a charity in the other’s name, for example. You also can accept an apology by phone if you cannot trust the other at the moment. The apology may make the face-to-face meeting in the future more possible.
If you choose to forgive and to reconcile, and if you have a measure of trust, then it is better to forgive and to apologize in person because you want to re-start the dialogue and establish trust. The process certainly can start by phone or email or some other social media, but ultimately, if you truly want a relationship with the other, then the best way is to do that is in person.