Free Photoshop Birthday Invitation Card Template
Another option is to use a pre-made template, which is what I normally do. When you download these templates they have all sorts of different elements in them, like hearts, roses, words, etc. Then you just pick the ones you want to use for your Photoshop birthday card. Then you fill in the details, such as your message, and put it in the envelope. Print it out and laminate it for a lovely touch.