I am taking Malayalam text from MS Word document in Rachana font and copying pasting to InDesign (Rachana font set as paragraph style) but there are glitches, errors and special characters appearing that are not there in the .txt
You need to turn on the World-Ready Composer. There are a few places to find it; in your Paragraph Styles, it's in the Justification section. If you're applying formatting locally, you can find it in the Justification dialog (Control + Alt + Shift + J while you have text selected).
You'd probably be better off using File -> Place to put your entire Word file into InDesign all at once.
You need to turn on the World-Ready Composer. There are a few places to find it; in your Paragraph Styles, it's in the Justification section. If you're applying formatting locally, you can find it in the Justification dialog (Control + Alt + Shift + J while you have text selected).
You'd probably be better off using File -> Place to put your entire Word file into InDesign all at once.