noun, noun or participle which takes 'suru'
one's own writing; handwriting; autograph
Refers to something written by oneself, often in formal or legal contexts. Can be used as a noun or with する to mean 'to write oneself'.
この手紙は彼の自書です。
This letter is in his own handwriting.
履歴書は必ず自
Please write your resume by hand.