Patch can be downloaded from Oracle Support site: link

All Upgrades: 730365.1

Patches & Updates → Recommended Patch Adviser → Select the necessary product

Don't forget that you must have also adequate OPatch tool from patch: 6880880

Patching of the Grid Infra is done in rolling fashion, meaning that the patching is done node by node, such way that the database can remain online and available. Of course there is option to patch both: Grid Home and Database home, but again, the database can remain online. There are two main ways to patch Grid Infra home:

(Patching 12.1.0.2)

1. Patch First node
2. Patch Second node

(Patching 12.2.0.1)

1. Patch First node
2. Patch Second node