If you use Farm account, It will give you warning in Health check issues like: the farm account should not be used for other services - Distributed Cache Service
You can use domain user for this service. You can not change user account from Central Admin. You can change the user account using below Powershell code:
add-pssnapin microsoft.sharepoint.powershell
$farm = Get-SPFarm
$cacheService = $farm.Services | where {$_.Name -eq “AppFabricCachingService”}
$accnt = Get-SPManagedAccount -Identity <domain\user>
$cacheService.ProcessIdentity.CurrentIdentityType = "SpecificUser" #provide here domain user
$cacheService.ProcessIdentity.ManagedAccount = $accnt
$cacheService.ProcessIdentity.Update()
$cacheService.ProcessIdentity.Deploy()
Wait until it has run, then you will find that the service has a new managed account.
Go back to the Health Analyzer report page and remove the alert.
Reference: