You can do both. You should ALWAYS write a formal resignation letter that's about 3 lines at most, before talking to the manager.

It just stops a ton of confusion, hope, etc. It allows that discussion to focus on "Do you want the two weeks?" and "What do you want me to do with those two weeks if you want them."

Part of being a good employee is making things clear to your manager.

I mean, if you want to burn a bridge you can do so. Sometimes it's warranted. However, if you have a good relationship with your manager then it's absolutely ideal to tell it to their face (or with a 1 on 1 call). It's not about guts it's about mutual respect. Likewise for layoffs.

Right. If situation allows doing face to face is nice. But thing as they are lately doing via canned message or email is perfectly fine and one need not think any less of manager or employee just based on their communication method.