initial

initial adjective [ always before noun ] uk/ɪˈnɪʃəl/ us
B2 first, or happening at the beginning

первоначальный
My initial reaction was one of anger.

INITIAL noun

[ C ] uk/ɪˈnɪʃəl/ us
B1 the first letter of a name

инициал
[ usually plural ] His initial s are S.G.M.
initial verb [ T ] uk/ɪˈnɪʃəl/ uspresent participle mainly UK initial ling | past tense and past participle initial led | present participle US initial ing | past tense and past participle initial ed
to write your initial s on something

ставить инициалы
Could you just initial that change you made on your cheque?