A round corner punch, which you can easily buy for under $10 is a great way to add some flair to any of your handmade invites or cards.
I use one for things like my e.m.papers business cards, and the tags I made for the goodie bags at the Advent workshop I hosted a couple of years ago.
This couple you used e.m.papers printable for components of their wedding stationery and the rounded corners really added a special touch.
The next time you’re in a hobby store, pick one up. Just by having it handy you’ll come up with all kinds of ways to use it!