If your system can re-order and produce conjuncts for Indic scripts aka Brahmic scripts, then this sequence of characters:

हिन्दी should look like this image: Hindi, which says "Hindi" in Hindi.

If the sequence looks like this image instead: Hindi sequence, your system is not re-ordering or producing conjuncts for Indic script.

To compose this word in Unicode, the characters are entered in this order:

1.    2. ि    3.    4.    5.    6. .

Unicode compatible software then:
  1. "re-orders" characters 1 and 2 so 2 appears to the left of 1,
  2. makes a "conjunct" (a sort of combination) of characters 3 and 4, and
  3. adds the last two characters, 5 and 6.
See also Help: Multilingual support (Indic) on Wikipedia.

Back to Assistance: Step 1, Displaying International Characters/Unicode