The Himalayan mountain system which includes outline sub ranges stretches across six countries Afghanistan Bhutan China India Nepal Pakistan

Is your question about whether the statement is true?

Yes, it's true.!

Let's list the countries from East to West: India, Bhutan, China, India Again, Nepal and China, then India Again, Pakistan and Afghanistan.

The only problem with this statement is that it actually stretches a bit further: to Tajikistan as well.