Attach clothes to an already rigged character

Simple, fast and basic way to put clothes on a rigged character

1. Select the clothes and then select the character
   
2. Go to Object --> Link/Transfer Data --> Transfer Mesh Data
   
3. Select 'Vertex Groups' in the tab that appears (Transfer Mesh Data menu)
   
4. Go to the bottom of your screen and under Source Layers Selection select 'All layers' and under Vertex mapping select 'Nearest Face Interpolated'
   
5. Select the clothes and then the armature, press control+P and select Parent --> With Empty Groups

Step 1

Step 2

Step 3