Getting syntax error while inserting data

NSERT INTO details ('Reference ID','Type of Request','User Start/Term/Change Date','User Full Name','Manager/Supervisor Name','Department U.S','Department International','User Temp/Contractor','Last date for Temp/Contractor','Computer Model','Other Equipment Instructions','Create Email Account','Other Email Instructions','Location for adding to DL','Distribution Lists','Remove from DL','Department Share Access','Other Share/s Access','Remove from department share/s','Personal Software-Vector NTI Standalone','Personal Software-Resharper','Personal Software-Matlab Standalone','Personal Software-Matlab Concurrent','Personal Software-Project Pro','Personal Software-Visio Std','Personal Software-Visual Studio','Personal Software-Perforce','Personal Software-JMP Annual','Personal Software-Solidworks Pro','Personal Software-Solidworks Premium','Personal Software-Kaleidagraph','Personal Software-SnagIt','Personal Software-Zemax','Additional Software','IT Ent App-SAP','IT Ent App-Agile','IT Ent App-Camstar','IT Ent App-QlikView','IT Ent App-HPQC','IT Ent App-Terminal Server Access','IT Ent App-Sharepoint','IT Ent App-CommVault','IT Ent App-SalesForce','IT Ent App-Amazon_S3','IT Ent App-RemedyForce','IT Ent App-Bugzilla','Other Needs') VALUES ('0','Request a new application or service','2020-10-30','test test','test test test','Select an item','405SGP - Service Singapore','on','2020-10-21','Macintosh MacBook Pro 13"-Standard issue small form factor Mac.(Smallest & lightest Mac form factor)','test test test test test test test test test test test','on','','on','on','on','DL-Test','DL- Test Test','
Test','
pbi','
fs\users','on','on','on','on','on','on','on','on','on','on','on','on','test test test','Remove','Add','Add','Add','Remove','Remove','Add','Add','Add','Add','Remove','Remove','test test') You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''Reference ID','Type of Request','User Start/Term/Change Date','User Full Nam...' at line 1

My code $sql = "INSERT INTO details('Reference ID','Type of Request','User Start/Term/Change Date','User Full Name','Manager/Supervisor Name','Department U.S','Department International','User Temp/Contractor','Last date for Temp/Contractor','Computer Model','Other Equipment Instructions','Create Email Account','Other Email Instructions','Location for adding to DL','Distribution Lists','Remove from DL','Department Share Access','Other Share/s Access','Remove from department share/s','Personal Software-Vector NTI Standalone','Personal Software-Resharper','Personal Software-Matlab Standalone','Personal Software-Matlab Concurrent','Personal Software-Project Pro','Personal Software-Visio Std','Personal Software-Visual Studio','Personal Software-Perforce','Personal Software-JMP Annual','Personal Software-Solidworks Pro','Personal Software-Solidworks Premium','Personal Software-Kaleidagraph','Personal Software-SnagIt','Personal Software-Zemax','Additional Software','IT Ent App-SAP','IT Ent App-Agile','IT Ent App-Camstar','IT Ent App-QlikView','IT Ent App-HPQC','IT Ent App-Terminal Server Access','IT Ent App-Sharepoint','IT Ent App-CommVault','IT Ent App-SalesForce','IT Ent App-Amazon_S3','IT Ent App-RemedyForce','IT Ent App-Bugzilla','Other Needs') VALUES ('0','$Type_of_Request','$Date','$Users_Full_Name','$Manager_Name','$Dept_USA','$Dept_International','$Temp_Contractor','$Last_expected_date','$Computer','$Other_Equipment','$Create_Email','$Email_instructions','$Menlo_campus','$Singapore_Campus','$Field_Campus','$DL','$Remove_from_DL','$Dept_share_access','$Other_share_access','$Remove_from_dept_share','$Vector_NTI_Standalone','$Resharper','$Matlab_Standalone','$Project_Pro','$Visio_Std','$Perforce','$JMP_Annual','$Solidworks_Pro','$Solidwork_Premium','$Kaleidagraph','$SnagIt','$Zemax','$Additional_Software','$SAP','$Agile','$Camstar','$QlikView','$HPQC','$Terminal_Server_Access','$Sharepoint','$CommVault','$SalesForce','$Amazon_S3','$RemedyForce','$Bugzilla','$Other_Needs')";

I am v new to MariaDB/SQL