The following example shows how to write Sanskrit using the nearest English letters for various Sanskrit online tools in this site. This convention used closely follows the mapping given in the www.unicode.org/charts for Devanagari alphabet.
First verse of Shree Suktam:
हिरण्यवर्णां हरिणीं सुवर्णरजतस्रजाम् । चन्द्रां हिरण्मयीं लक्ष्मीं जातवेदो म आवह ॥१॥
English to type in the Sanskrit Writing Pad or other tools:
व्ँव
English to type in the Sanskrit Writing Pad or other tools:
v-!1$1va
Note how each Sanskrit letter is generated by typing the nearest English letter. Conjoined letters are represented using the -(hyphen) symbol between the letters. Parenthesis could have been added optionally to enhance readability by grouping certain words. A little practice will make the rules clear.
Remember these simple rules:
Type the characters given in the square brackets next to the Sanskrit letters.
e.g. Type sa for SA, ha for HA etc.
All characters to be typed are in lowercase only.
A long letter is represented by twice of short letter.
e.g. a for A and aa for AA; type i for I and ii for II etc.
Use hyphen (virama) between letters for half forms.
e.g. Type s-t-ra for STRA.
Use parenthesis if grouping is required for readability or ambiguity
e.g. (s-t-ra) for STRA