It depending on the model number of that breaker box some can have room and some don't so either post the model number or take a photo one of us will able indentify it.
Just be aware when you take the cover off from older breaker box some case the breakers may fall out of the place so the safest way is turn off the power at the meter socket location most mobile home will have extreal disconnect switch so use that before you open up the panel box.
A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Come join the discussion about tools, projects, builds, styles, scales, reviews, accessories, classifieds, and more! Helping You to Do It Yourself!