Hi @JeanG1223 ,
Here are steps：
- Create a single line of text column (Name email during testing)
- List setting-> Validation setting
- Enter the formula: =OR(RIGHT(email,LEN(email)-FIND(".",email))="edu",RIGHT(email,LEN(email)-FIND(".",email))="gov",RIGHT(email,LEN(email)-FIND(".",email))="mil")
The demonstration results are as follows. When you create a new item, you can only enter the content with the suffix of .mil, .gov, and .edu. Otherwise, an error will be reported and the creation cannot be successful.
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