Primary keys in a single column table and text vs varchar

I am designing a table that will hold a list of unique names and be
referenced by several other tables. There will only be one column in the
table (name), should I still create a separate primary key for that column
or can I use the name column as my key. I have also been reading a lot
about the differences between varchar and text and was wondering if there is
a downside to using text. The column I want to use text on (notes) will
hold a string that could be any length, I can use varchar(255) but I am
worried about the text being truncated or of the queries giving errors when
I try to output the text. I understand there is a mathematical limit to how
much can be stored in a single entry but I wasn't sure of any downsides to
just defaulting to text when possible.

Thanks,

Matt