Tip 1: Don't label it with a pencil, you'll just end up with a messy smudge

Use a permanent marker, for crying out loud. It's 2023, not 1923.

Subtips:

• Make sure it's not a Sharpie, those things bleed like crazy
• Try to aim for the center of the envelope, you don't want to be that person who labels the whole thing with a 2-inch margin

Next: Tip 2: Use a ruler, but only if you're feeling extra fancy