Under subsection 33(1) of the Construction Act
https://www.ontario.ca/laws/statute/90c30#BK78
Allowed extensions pdf, doc, docx, jpg, jpeg, gif, png, tif
For "A" - If a lien attaches to the premises, a legal description of the premises, including all property identifier numbers and addresses for the premises
For "B" - If the lien does not attach to the premises, the name and address of the person or body to whom the claim for lien must be given