Display a message when button is clicked

Kinda depending on exactly where this button is and what other things you're expecting it to do, one feature you might be able to make use of is the "Confirmation Message" configuration which gives the user a pop-up (where you can make the message whatever you want), along with ok / cancel buttons (where you can change their labels but not what they do), and they have to press the "ok" button for the base button to take effect.

Hi Mike and Richard, 

The button is for exporting a grid to excel and when an user clicks it, an email is sent with the excel spreadsheet as attachment. 

So I want to inform the users to check their mail. 

I don't want to keep it as a confirmation message. 

Thanks

Hi Mike and Richard, 

The button is for exporting a grid to excel and when an user clicks it, an email is sent with the excel spreadsheet as attachment. 

So I want to inform the users to check their mail. 

I don't want to keep it as a confirmation message. 

Thanks

From the user's perspective, what will happen after clicking the "export to excel" button, other than the export being emailed to them?  Does the process end?  Or do you want them to remain on / return to the same form?

Once the email is sent, the document is deleted and the process ends. But the user can continue to remain on the same form to perform other tasks like creating an asset etc.,

What about using a record action there?

Is there any other option? 

The old stand-by option is to have the "export to excel" button submit the form, route to the correct process flow via an XOR gateway, and take the user to a separate User Input Task with the simple Confirmation Message indicating that they should check their email shortly for the exported Excel.  From there they would only have the option to click an "OK" button (for example), which would route them back to the original form.  While they're on that confirmation form, a separate process flow would already be handling the excel export and email.

ETA: this would look something like the following sketch:

i would insert just a show when condition for a text line or boxlayout which is appearing  right besides or below the button. 

Would love to try this method. Could be handy in future projects. 

Thanks Mike.