There are total 20 whmcs templates included for you in the WHMCS/templates folder of your purchased zip file (Maxhost - Web Hosting and Corporate WP Theme.zip). The 20 templates are:
1. maxhostaltv812-tw[*Recommended]
2. maxhostaltv812
3. maxhostaltv811-tw
4. maxhostaltv811
5. maxhostaltv810-tw
6. maxhostaltv810
7. maxhostaltv89-tw
8. maxhostaltv89
9. maxhostaltv88-tw
10. maxhostaltv88
11. maxhostaltv87-tw
12. maxhostaltv87
13. maxhostaltv86-tw
14. maxhostaltv86
15. maxhostaltv85
16. maxhostaltv84
17. maxhostaltv83
18. maxhostaltv82
19. maxhostaltv81
20. maxhostaltv80
You need to use just 1 of them in your WHMCS installation. Which one? It depends on which version of WHMCS you are using.
Here we are going to explain more so that you can choose the correct one for you:
As we mentioned in Maxhost Theme Details page of ThemeForest, we do NOT give support for any WHMCS issues. WHMCS is not related to WordPress. You will be able to install WHMCS once you purchase WHMCS License from whmcs.com, and you should get support for your WHMCS from WHMCS support team once you got the WHMCS License. If you do not have a WHMCS license yet, you cannot use our custom WHMCS template, you can use our Maxhost WordPress theme only. To use custom Maxhost template for WHMCS, you need to have a WHMCS license and install WHMCS in your server.