なna-adjective
necessary
hitsuyouda
meaning: is necessary
state
feeling
examples
予約は必要ないってさ。
yoyaku wa hitsuyou naitte sa.
Apparently no reservation is needed. casual
ご記入の際は、印鑑が必要となります。
go kinyuu no sai wa, inkan ga hitsuyou to narimasu.
A seal is required when filling in the form. formal