1. Character Limits Multiline text box
string-length(.) > 1000 (two rules 1. Validation and error message, 2. set the counter as action)
2. Character Limit for Text Box – we have option in TextBox property
3. Label Box – Set Textbox property as read-only
4. set a action
All Upper case – translate(., “abcdefghijklmnopqrstuvwyxz”, “ABCDEFGHIJKLMNOPQRSTUVWYXZ”)
5. To permanently delete a field from an InfoPath form template, delete it from the Main data source
6. A quick way to find out whether there are rules, data validation rules, calculated default values, or code present within an InfoPath form template is by using the Logic Inspector. The Logic Inspector is especially handy if you have large and complex InfoPath forms with many controls and business logic. You can access the Logic Inspector by going to the Tools menu and clicking the Logic Inspector menu item.
Note:
InfoPath functions with examples http://www.bizsupportonline.net/infopath-functions-examples.htm