You can set any webpage as your homepage, and have it shown when you open a new window or a new tab.
Change homepage settings: Choose Safari > Preferences, then click General.
Set your homepage: Enter a webpage address in the Homepage field, or click Set to Current Page to use the webpage you are currently viewing.
Open new windows with your homepage: Click the “New windows open with” pop-up menu, then choose Homepage.
Open new tabs with your homepage: Click the “New tabs open with” pop-up menu, then choose Homepage.
Quickly open your homepage: Choose History > Home.