Place the paper under a heavy, flat object for several hours or overnight
Put the paper between two clean sheets of plain paper or parchment paper
Use a warm iron on the lowest setting
Keep a thin cloth or another sheet of paper between the iron and the wrinkled paper
Move the iron gently and briefly across the surface
Avoid using steam unless the paper is very sturdy
Press the paper with books after ironing
Use a paper press or stack of heavy books for a longer period
Lightly mist the paper if needed, then press it flat immediately
Let the paper dry completely while pressed
Handle the paper carefully to avoid new creases