Can I do a free form search?
If you mean a search that will look at all the field at the same time no.
But in template you have some search for hostname/user/ip, that will search in all the relevant fields.
Can you please breif your requirement?
For which product you are looking for free form search?
You can search in the raw event field which will allow you to search across all the original event fields provided you have enabled raw event logging. However such a query will take a lot of time unless resticted to a time interval and a particular product. Moreover such a query will not give you accessed to any derived and normalized fields.