Thank you very much for your input.
Can I also create physical standby database with dbca/GUI,etc ?
No. DBCA is use to create a new database.
Standby Database is not a new database, it's a replica of your production database.
oracle should be installed on the server where you want to create standby database.
for your reference i am giving you one more links.
This is different method.
chose which ever you find appropriate
ASM Instance through Grid Control should be setup first on Standb DB first, right?
The links describe as backup location or storage as local disk (Not with ASM). I wounder scp command would work from Primary to Standby while copying everything.
I have a test single instance db. I was thinking, If I install software only option on the same machine and create a Standby Database just for the testing purpose, as I have little time for preparation. What do you suggest?
It is always a best practice to test for yourself. while doing doing so you will realize what all are require and where you are going wrong. So while doing it on production you will be aware of it and all the issues will be solved easily.
Yes, that is obviously true what you said, but I was just asking if it makes sense or possible to create PRIMARY and PHYSICAL STANDBY DATABASE on the same HOST?
Yes it is possible to create on the same host.