In general, interface text such as labels, page headings and system messages cannot be changed. However, there are several areas which you can override. 

Example: A common system label that many Grant managers change to better suit their program is the Application name label in the application process.

You might want it to say Applicant name instead, example: 

To make this change:

1. Go to Settings > Content > Interface text
2. Under Entries, choose Entries form title label (see the list below for other available options)
3. Enter the text to be used for the label in the box below
4. Click Save
5. Refresh your browser and go back to the application to see this update

Common interface text options to change

1. Application name field (entries.form.title.label)
2. Application name field help text (entries.form.title.help)
3. Add link or video on Attachments tab (entries.form.add-link)
4. My applications when no applications are present (entries.no_entries.message)
5. Application name column title (entries.table.columns.title)
6. SAML login button (home.login.saml)
7. Reviewing view heading 'Comment on this application' (judging.form.comment.heading)
8. Menu title for 'About' pages (content-block.menu.links.about)
9. Phone number validation failure message (validation.phone_format)
10. Field validation failure message (miscellaneous.alerts.validator.message)

There are many more: