Gmail would not allow to attach .exe format file.If you try to attach an executable file(.exe) then Gmail would prompt a message saying “file is an executable file. For security reasons, Gmail does not allow you to send this type of file”.
But still if you need to send a executable file in Gmail there are some workarounds
Rename the file
Rename the file without .exe extension.For eg if the file is “test.exe” change it to “test.txt” and attach in gmail for sending.
Communicate in the receiver side that they have to change it to .exe extension.
Compress the file
Compress the file using any tool and the attach it in gmail.For Eg if you compress using the winrar tool it will be compressed and extension would be “test.rar” which Gmail would allow to be attached and sent.
These workarounds would violate Google policies.Thus if you wish to go with Google,upload the file in some file sharing website and give the link in the mail.