Mandarin has four main tones plus a neutral tone. In print, the usual academic form puts a mark on the vowel: mā, má, mǎ, mà. In chat, dictionaries and some keyboards, people write ma1, ma2, ma3, ma4. Neutral tone is often ma5 or unmarked.
When marks are better
Teaching materials, linguistics papers and anything that should look like standard Pinyin use marks.
When numbers are better
ASCII-only forms, quick notes, and input boxes that cannot store combining marks. The Pinyin Writer is built for that: type ma3 and get mǎ.
Neutral tone
The fifth "tone" is weaker. Different teachers mark it differently. If a tool asks for 5, that is the convention this writer documents in its hint text.
Generate marks from characters with the Pinyin converter. Learn the contours in the four tones.