i work at a software company. why we don't use 'am' after 'i'

because hear is a verb word

''work at software company'' is habitual action. for habitual action ,we use simple present tense . and in simple present tense we don't use 'am' with ' i '. If you want to describe information about something at that time you can use 'am' with ' i '.

Because here is a verb "work".