To have the ability to check when creating a new record to see if a similar record already exists; ie. ‘John Smith’ and ‘John Smith’, a warning pop up ‘A record with that names already exists’. Make it customisable on selected fields.
The easiest way is to mark the column as unique.
In case you want to customize it, you need Workflow Automation and check the values before save.
Brilliant! Thanks that solved my problem