To customize client information fields and re-arrange their order, go to Settings > Preferences > Client Info Fields. Field labels and their order will be reflected in the client's profile and on the booking page. To change the order of the fields, click the grey bar on the left side of each field and drag and drop accordingly.
For example, let's rename 'Last Name' field into 'Dog's Name' field by clicking 'Edit' link and modifying the name.
The option 'Visible to clients on your booking page' will allow your clients to see the field when booking online. 'Required' option will make that field required when clients book online.
Now, your clients will see modified field (i.e. Dog's Name) on your booking page.
In the client's profile, 'Last Name' field will also be modified into the 'Dog's Name' field.
Registered clients will also see all 'visible to clients' fields in their client accounts.