As a site collection administrator, you can choose regional settings for all users of the site. Individual users can choose to use your default settings or specify their own personal settings, which would override your site-level settings. To change your personal settings, see Change your language and region settings.
Change regional settings for a site.
You must be signed in as a site collection administrator to change regional settings for a site.
From a site page, click the icon for Settings , and then click Site Settings.
On the settings page, in the Site Administration section, click Regional Settings.
Update the regional settings and click OK.
As a site owner, you can choose the following regional settings for your site: