I need help to update safari

macOS

Try suggestions given in this article.

https://support.apple.com/en-gb/HT204416

iOS

Safari is installed and maintained as part of iOS

https://support.apple.com/en-us/HT204204

Safari is installed as part of the operating system and it normally it cannot be individually upgraded. It is periodically updated when the computer's operating system is updated or upgraded. If you are having problems on some web sites you can use another browser that does work such as Firefox or Chrome. They can be individually updated as needed. Finally, even if you are able to update Safari, there is no guarantee that it will be compatible with every web site.