Currently we are using an auto generator sitemap, but this sitemap does not show the date & time, then how can added a date & time?
By using a custom sitemap. A manual process that you would need to maintain when adding new items.
Yes, I know to add the custom code but this process is a manual process, I am going to every time manually change the sitemap, can you suggest any other solution provide some like Third party integration? so when I update the website that time auto change the custom sitemap.