HP LaserJet Enterprise M4555 MFP series - Manual (Page 117)

Load Tray 2 and optional Trays 3, 4, and 5 with custom-size paper
1. Open the tray.
2. Adjust the paper-length and paper-width
guides by squeezing the adjustment latches
and sliding the guides to the size of the paper
being used.
3. Load paper into the tray. Check the paper to
verify the guides lightly touch the stack, but do
not bend it.
ENWW Load paper trays 97