there is one user who has only read access to account and contact object and their tabs are hidden. i want to global search the record but in lightning record doesn't seaaarch but in classic i get the record.
Global search in Lightning Experience and Salesforce Classic uses the same search index, so you're always searching the same data. You see the same set of recently accessed records in instant results. The search scope (the list of objects you use the most) influences search results, but some standard objects aren't available in Lightning Experience. You don’t always see the exact same search results. Lastly, the global search interface is different between these experiences, so there are visual and navigational differences to consider.
Review below links which can give more information.
Global search in Lightning Experience and Salesforce Classic uses the same search index, so you're always searching the same data. You see the same set of recently accessed records in instant results. The search scope (the list of objects you use the most) influences search results, but some standard objects aren't available in Lightning Experience. You don’t always see the exact same search results. Lastly, the global search interface is different between these experiences, so there are visual and navigational differences to consider.
Review below links which can give more information.
https://help.salesforce.com/articleView?id=000330207&type=1&mode=1
https://help.salesforce.com/articleView?id=search_desktop_mobile_comp.htm&type=5
https://help.salesforce.com/articleView?id=lex_gaps_limitations_search.htm&type=5
Thanks,
Vinay Kumar