Grant Permissions to Folder Share 
Grant-SmbShareAccess -name $ShareName -AccountName $Account -AccessRight Full -Force
Details
Grants share permissions to a user or group

Example
PS C:\> $ShareName = 'ScriptFiles


>> $Account = 'Domain Admins'
>> Grant-SmbShareAccess -name $ShareName -AccountName $Account -AccessRight Full -Force


Name                    ScopeName               AccountName             AccessControlType       AccessRight
----                    ---------               -----------             -----------------       -----------
ScriptFiles$            *                       DOWST\Domain Admins     Allow                   Full
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Revoke All Permissions From Folder Share 
Get-SmbShareAccess -name $ShareName | Foreach {Revoke-SmbShareAccess -name $ShareName  -AccountName $_.AccountName -Force}
Details
Gets all the permissions for the share, then revokes them.

Example
PS C:\> $ShareName='ScriptFiles

>> Get-SmbShareAccess -name $ShareName | Foreach {Revoke-SmbShareAccess -name $ShareName  -AccountName $_.AccountName -Force}


Name                    ScopeName               AccountName             AccessControlType       AccessRight
----                    ---------               -----------             -----------------       -----------
ScriptFiles$            *                       NT AUTHORITY\SYSTEM     Allow                   Full
ScriptFiles$            *                       *S-1-5-5-0-158796760    Allow                   Read
ScriptFiles$            *                       *S-1-5-5-0-158796760    Allow                   Read
ScriptFiles$            *                       Everyone                Deny                    Full
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