Your information is stored in your Roku account at https://my.roku.com. All Roku devices connected to this same account will have access to this info. Any channel added or deleted from one will be added or deleted for all. (Exception some newer channels may not be compatible with significantly older units, and won't install on them.)
The things specific to each Roku device that must be set on each device are your logins to any subscriptions not purchased through Roku, and the order of the channel tiles in the channel grid.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T
I I am thinking about buying two Roku devices I was wondering if I log into one record of ice if my passwords and stuff for Netflix and Hulu would go onto the second one automatically.
Those apps specifically? I don't think so. However, there are some apps that use Roku's Single Sign On process that will function like you're thinking. As @makaiguy some data is stored by Roku. But not everything on each box is stored by Roku. Complicated legal reasons, or complicated "that's a lot of work to do that" reasons, etc.
Anyway, you may find, as I did, that some apps that are set up on one device will automatically log in when a new device is added to the same Roku account. But certainly not all.
Hulu wasn't one of those the last time I added a Roku device. And I haven't dealt with Netflix in years, but I don't think they do that either.
Some apps do work that way, but not those.
DBDukes http://www.dbdukes.com/Roku Ultra (4660) Roku Streambar (9102) Roku Streaming Stick+ (3810)