App for e- way bill

no
it is only generated though https://ewaybill.nic.in/Login.aspx

yes it is available.pls see online in play store.

An eway Bill is an 'electronic way' billfor movement of goods which can begenerated on the eWay Bill Portal. ... E-way bill can be generated or cancelled through the e-way bill website, LEDGERS GST Software, SMS, AndroidApp and by Site-to-Site Integration (through API).

Follow this link.

https://play.google.com/store/apps/details?id=in.ewaybillgst.android

E way bill is to be generated through e way bill web site.