With a sheet of normal paper and simple glue you can create envelopes of any size. This is a quick and easy process that even a 5-year-old can follow (under adult supervision). It's a perfect way to personalize a birthday card even more.
Steps

Step 1. Place the greeting card on a 210 × 297 mm large sheet of paper (basically an A4)
Arrange it horizontally, shifted slightly towards the bottom of the paper. If you don't already have a note available, make a mark on the paper where it should be placed.

Step 2. Fold the sides of the paper inward
Leave some space between the fold and the card so that the envelope is slightly larger.

Step 3. Press firmly on each fold to flatten it well

Step 4. Do the same with the top and bottom folds
Remember to always leave some space between the fold and the card.

Step 5. Now open the sheet of paper and remove the card

Step 6. Now remove the corners
Make cuts a little wider than 90 degrees.

Step 7. Break off the first corner

Step 8. Repeat the process for all other corners
Make sure the envelope fits the card without any problems before applying the glue.

Step 9. Fold the sides of the paper again, put some glue in the bottom corners and fold the bottom side back to glue

Step 10. Measure for another piece of paper that is slightly smaller than the envelope
This is the back of the envelope and will be used to close it.

Step 11. Glue this piece of paper along the bottom and side edges of the envelope, then gently squeeze

Step 12. That's it
You made an envelope! Insert the greeting card inside and close it with a drop of glue.
Advice
- It's a fun and easy project to make even with kids!
- Work on a clean surface.
- You should use vinyl glue or duct tape. Anything else would make the paper wrinkled.
- To give the envelope a more personal touch, you can print something on the paper, such as hearts, flowers, phrases or even a child's drawing previously scanned.
- Remember that this can be difficult for a child, so let an adult help you.