Any time you create a document that has image area that you want to print all the way to the edge of the page, you need to allow enough bleed so that when the document is cut, you will not run the risk of having white space showing due to the paper shifting during the printing/cutting process. Any document that requires bleed will actually be printed on a larger piece of paper and then will be cut down to the final size. So when you create your document the image area needs to extend beyond the edge of the page.
Again, using a business card as an example: the final cut size of the business card will be 3.5” x 2” but because the business card bleeds, the size – using .125” (1/8”) bleeds will be 3.75” x 2.25”. I prefer using InDesign to create layouts, not that I don’t use Illustrator and Photoshop, but in your initial file set up, you give 3.5” x 2” as the document size and .125” for bleed size and the document will easily show you where your bleed area and regular image is located. Then when you create your pdf just be sure to include crop marks and use the document bleed settings.
Here is a business card showing crop marks but no bleeds.

And here is a business card showing crop marks with bleeds.

Depending on the printing company and the type of job, you may have to pay extra for a document with bleeds so it is always good to specify whether your document bleeds.