SharePoint 2013 does not support "Save Site as Template" option on Publishing sites. If a site with "SharePoint Server Publishing" is activated this option will not available in Site settings, So you can't save site as template. What should we do?
Enable Save site as template SharePoint 2013 with SharePoint Designer
Open SharePoint Designer 2013.
Open Web application which you are not able to see ”Save Site As Template” options.
In the home page of SharePoint Designer 2013, there is a option: “Site Options” in the top Ribbon
Click on “Site Options”, you will get prompt, In the “Parameters” Tab, you can find “SaveSiteAsTempalteEnabled”
Check what is the value for “SaveSiteAsTempalteEnabled”, if it is a false.
Click on Modify..
Change to True.
Save
Close
Now, When you access the save site as template URL you should be able to get the save site as template page.
Or Enable Save site as template SharePoint 2013 with PowerShell
Add-PSSnapin Microsoft.SharePoint.PowerShell
$SiteURL ="http://intranet.crescent.com/sites/operations"
$web = Get-SPWeb -Identity $SiteURL
#Enable Save Site as template option
$web.SaveSiteAsTemplateEnabled = $true
$web.Update()
