Go to
Content search - Microsoft 365 compliance
Then Content Search-->on Search--> Start Search with .+New Search--->Enter Name and description--->next-->select Location--it may be Exchange (You can include here the mailbox you want to search )/SharePoint sites/Exchange Public Folder--->Next-->can apply different conditions here, like sender/date/recipients etc...--->Next----> Review the search---click on submit
now you can monitor the status of Search in the Search tab, it may be in starting/completed etc. status.
and once completed, click on it and at the bottom click on Action and select Export result.
Now go to Export tab and here you will see your search name as the nameofSearch_Export.
Another window will open and here in the mid of the window, will see the status as preparing data/completed etc. and may wait for the status to be completed or you can start the download. To start The download, from the top of the window click on download result.
A small window of eDiscovery export tool will open, asking for Export key and location on your system where you want to save the result.
in the eDiscovery tool you can monitor the status of the download and once completed you may have a folder at the downloaded locations like (D:\Nawaz\SearchName_Export\12.25.2021-1659PM\Exchange)
here you will find your pst file/files.
