Adverb
In a legible manner.
Source: Webster's dictionaryyou must write legibly Source: Internet
This indicates that terms and privacy policies should be laid out legibly () using understandable language and clauses so that users are fully aware of what they’re consenting to and what the consequences of their consent are. Source: Internet
Thing is, I looked at the letter and just thought the person was trying to write legibly. Source: Internet