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Salesforce P1Salesforce P1 

how to get base URL in Process Builder or Flow without any extra field creation

Raj VakatiRaj Vakati
You can use the label .. that is the only 
  1. Either you create an output text variable
  2. Or  Use the labels 

Or use
 
LEFT($Api.Partner_Server_URL_340, FIND( '/services', $Api.Partner_Server_URL_340)) & Id

Refer this link

https://salesforce.stackexchange.com/questions/81905/salesforce-baseurl-in-process-builder​​​​​​​