One of the central rites of Vorinism is burning said prayers. This is considered to be the only way to actually communicate with the Almighty.
There appears to be no constraint on the form beyond that they must be written down in glyphs and lit on fire. This is also the only written language which men who are not of the ardentia are allowed to use.
Glyphwards could thus be used to invoke or protect against the power contained in their names, such as to ward off evil from one's home; appeals to protect loved ones; prayers for success, blessing, justice, or thanks.