Mudra is a major part of yoga. Most of the mudras done in yoga and pranayama need to use whole body and done with one or other yogasans (i.e. padmasana), but some are very easy and perform anywhere and involves only hands.
Some of these mudras are described here.
Application has description of how to perform mudras with pictures and also its benefit on health.
All the information given here is from various sources. It may be incorrect because for yoga there was not any major authentic source is available.
9Apps 4.9
