expression, godan verb (-ku)
print; write in block letters
Refers to writing or producing text in a printed style, as opposed to cursive handwriting. Often used when filling out forms or writing clearly.
申込書は活字体で書いてください。
Please fill out the application form in block letters.
印刷する means to print using a machine or press, while 活字体で書く emphasizes writing by hand in a printed style.
Compound of 活字体 (printed style of characters) + で (particle) + 書く (to write).