There is no one definitive answer to this question, as beta writing on a phone can vary depending on the individual's preferences and writing style. However, some tips on how to beta write on a phone may include using a word processor such as Adobe Acrobat, using an app such as Grammarly or OneNote, or using a free app such as Spellchecker for iPhone or Android. Additionally, it may be helpful to consider using a beta writing service such as PublishIt or Hootsuite to help manage and track beta writing progress.