A professional paper uses two different numbering systems to distinguish between the "Introductory" material and the "Main Body."
Front Matter: Use lowercase Roman numerals (i, ii, iii, iv). The title page is technically page "i," but the number is usually not printed on it.
The Main Body: Starting with the first page of your Introduction or Chapter 1, switch to Arabic numerals (1, 2, 3).
Placement: Page numbers should be placed in the Top Right corner or Bottom Center. Check your department guidelines for the preferred location.
A common habit from older typing standards is placing two spaces after a period. CMOS requires only one space between sentences. This keeps the "rivers of white space" in your document to a minimum, ensuring a professional, compact look.