I have recently got a new iPhone. Can you please assist me in backing up or restoring my pictures, videos, documents that were in my old iPhone to the new one. I am still using the same apple ID

if you can’t access to your old iPhone unfortunately you will not be able to backup it, If you backed up before your old IPhone crashes you can restore it when you set up your new iPhone See ☞ Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Hey there,

the first thing you have to do is back up your old iPhone See this article to learn how to do that ☞ How to back up your iPhone, iPad, and iPod touch - Apple Support

and then you can use quick transfer from your new iPhone, but if already setup your new iPhone you need to reset it to factory settings to be able to use quick transfers See this article to learn How to factory reset your iPhone, iPad, or iPod touch - Apple Support

after that see this article to learn how to Use Quick Start to transfer data to a new iPhone, iPad, or iPod touch - Apple Support

You can also watch this video:

https://youtu.be/kb7u-N_rFE4