Some typewriters have useful paper supports like the Smith Corona "Rabbit's Ears" or the Olympia fold up extending support, but others need help.
I've worked out a simple, fast solution that works for my Remington Quiet Model 1, and may work for your typewriter too.
You need a popsicle stick and a spring clothespeg:
Remove one side of the spring clothespeg, and substitute the popsicle stick:
Make sure the end of the popsicle stick doesn't go past the clamping end of the clothespeg.
Depending on the paper table of your typewriter, you might want to trim off a piece of the clothespeg end, like this:
Clip this onto the middle of the typewriter paper table, with the popsicle stick towards you, and you are ready to read the whole of your page as you type: