I am new to salesforce and currently working on LWC related project. I got a requirement to use aura inside LWC but I heared that salesforce is going to withdraw aura component stuffs. Is it true?
It is not correct that Salesforce will withdraw Aura Component stuff (Its not documented anywhere so unless you see in any official docs its not true). Salesforce supports both the programming model (Aura and LWC) and you can always use LWC inside aura components while other way round is not possible.
Salesforce has excellent documentation on when to choose Aura vs LWC. Below is what is officially recommended
Always choose Lightning Web Components unless you need a feature that isn’t supported.
If you need to use an unsupported experience or feature or use an unsupported interface, do most of the development in Lightning Web Components. Wrap your finished component in an Aura component that simply accesseses the experience, feature, or interface.