'filled' is the past tense and past participle of the verb 'fill.' As a verb, 'fill' means to make full or occupy space by putting something into or on something else. It can also mean to occupy a position or role.
She filled the glass with water.
The auditorium was filled with people eager to see the performance.
After a hearty meal, he filled the role of the main speaker at the event.
The aroma filled the room, making everyone's mouth water.
'Filled' can be used both transitively (with a direct object) and intransitively (without a direct object). For example, 'She filled the jar' (transitive) vs. 'The jar filled quickly' (intransitive). 'Filled' can also be used in a figurative sense, such as 'He filled the role of a mentor' or 'The news filled her with joy.' Avoid confusing 'filled' with 'feel' or its past tense 'felt.' They are entirely different verbs with different meanings.