In this post we will discuss how to hide ribbon in infopath 2010 in sharepoint 2010. If you are using infopath 2013, then you can see this article
on how to hide ribbon in infopath 2010. Apart from this you can also check:
You can hide the show or hide the ribbon in infopath 2010 easily through the forms option dialog box.
Follow below steps:
Open infopath 2010 form, go to File -> Info -> Form Options as shown in the fig below:
This will open the Forms Options dialog box.
There uncheck the "Show InfoPath command in Ribbon or toolbar" checkbox in the Web Browser category as shown in the fig below, then click on OK.
Now publish the infopath form, the ribbon will not come.