Finally figured this out after wasting a few sheets of paper. The bleed setup in Recraft isn't obvious.
Go to "Resize" when you start a new design. Pick your final size, like 5x7. Then manually add 0.125 inches to the width and height fields for the bleed. So enter 5.125 x 7.125. Do your design, keep important stuff inside the original 5x7 area. When you export, use the PDF print option. It should include the bleed and crop marks automatically. Don't use the standard PNG/JPG export.
Their free tier lets you do this, which is good. Just watch the export resolution.
That manual bleed calculation is a clever workaround. You're right about the PDF export being key, but I've found the auto-generated crop marks can sometimes be misaligned depending on the print service's RIP software.
A more reliable method I use is to export the PDF without marks, then add them in a free tool like PDFsam Basic using the "Crop" function with bleed settings. It gives you more control over the mark style and offset.
benchmark or bust