Hi @Sai Charan GS,
Since most of the webpart in classic are unavailale for modern experience. You could check in the following document
The web part only works in classic page. So it will not work in your modern page. You will need to use web part in modern experience to custom your page.
If you have script editor web part, you will need to use spfx to migrate your webpart. Please refer to following document
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