Use print guidelines to ensure content is in the correct place and does not get cut off.
TRIM / CROP
Trim size represents the area that is going to be cut. Trim lines help avoid narrow slivers of white at the edge of your document once it is cut to size. Trim is measured by “crop marks” which you can enable to view in your PDF by clicking Download > Show Crop Marks
The safe area is the area inside the trim. Safe area is a smaller dimension of your final print and is important to pay attention to because this is where you should place all the content you do not want to be cut. Any content outside of this area is at risk of being cut off.
The safe area can also account for the gutter, or middle, of the publication and how easy it will be to see content in the center of a print. Safe area on many print ads can be as little as 0.125” or as large as 1”. If your document is going to be a poster that will also be displayed within a metal frame, the safe area might be even larger to accommodate the overlap from the lip of the frame.
It is recommended to keep your content within the "margin" of your document (usually 1 to .5 inches away from the edge)
Bleed is the portion of your design that extends past the trim size. Bleed is cut off when the publication is trimmed to the final size. Its sole purpose is to make sure your design or image reaches the very edge without leaving any unsightly white edges. Bleed is commonly 0.0625” – 0.5” larger than the trim size but it really depends on the document size and how it will be trimmed.
Learn more about setting up bleed settings here.