Composition Taxpayer Interstate Supply

As per the GST Act 2017, A Composite taxpayer cannot engaged in making inter-state outward taxable supplies but can make inter-state purchases.

A composition Taxpayer doesn't collect tax on sales or neither he mentions GSTIN number of recipient of goods, then there is no way to identify whether it's intra or inter state supply right?

As per Section 10 of CGST Act A person engaged in making any inter-State outward supplies of goods are not eligible to Registered under composition scheme.
So, if you are under composition scheme, than you can not make inter state supply of Goods.

Yes, You can not charge/collect GST in your bill of Supply, whether its to Registered party or unregistered party.You have to pay tax.

if you are selling goods to Registered party than you are required to mention GST number of party.
So, by that it can be identified, it's inter or intra

If sold to unregistered person, and consignment value is more than 50,000 than you are required to make e way bill, by that it's identify it's intra or inter.