Montessori classrooms don’t use lined paper for teaching early penmanship. In the beginning, it is more important to lean how to write the letter. Also, children are taught only cursive letters for writing. Teaching children how to write one way, and then another way is very confusing and frustrating for grade school children.
Here is a free printout of the Montessori sandpaper cursive letters we used for penmanship.
Miss Homfray has a great video lesson about teaching writing in the Montessori classroom.