Respectfully means "with respect or deference." Respective, an adjective, means "relating to two or more things considered one by one." Respectively, the adverb form of respective, means "singly, in the order mentioned."
All people should be treated respectfully at work.
The three project team members made their respective
The first, second, and third elements identified in the sample were oxygen, fluorine, and hydrogen,
Respective and respectively can often be omitted without loss of clarity.
The three project team members made their [respective] presentations.