Yes, you can definitely add more details in your invoice header, s-sayeeharshiny-.
Once you have set up your GST, the GSTIN will directly appear on your invoice template. To set it up, just click the Taxes menu. In addition, you can add your PAN to the template.
For more details in customising your sales forms, you can click here.
Feel free to mention me in your reply if you need more help. Take care!