Can my Shopify app alter the admin dashboard UI?

[SahilRohera]

is that possible that my Shopify app can make UI changes or additions to the Shopify admin dashboard ??
if that cant be done with a public app then what other?

[product_options]

We cannot modify existing UI using apps. Though there are certain areas where we can render our app component. Like in order details page, product details page etc.

You can find example and documentation here

https://shopify.dev/docs/api/admin-extensions

[SahilRohera]

Thanks for the reply ... 
one more doubt ... what is more preferrable - building an app or this ui extensions for some extensive tasks ??

[product_options]

It depends on the tasks you planning to do. What are the tasks you need to achive?