My people book most of holiday site, something much used in lockdown (6)
I believe the answer is:
webcam
'something much used in lockdown' is the definition.
(camera used for video calls)
'my people book most of holiday site' is the wordplay.
'my people' becomes 'we' (we, people including me).
'book' becomes 'b' (abbreviation for book).
'most of' means to remove the last letter.
'holiday site' becomes 'camp' (camp site).
'camp' with its final letter taken away is 'cam'.
'we'+'b'+'cam'='WEBCAM'
(Other definitions for webcam that I've seen before include "Internet spy" , "Internet viewer" , "It sends visual images via the Internet" , "Internet-linked camera" , "Computer video device" .)