Which format should I use to submit a paper for review? I am going to submit a paper to the journal of ACM Transactions on web, there is an option for attached files named "File for reviewers". I guess it is the option I should choose, but I don't know in which format the file should be. As I searched the site there are a word and a latex templates for articles, but they might be for the final version of the paper?

Can I submit it as a unformatted word document, but enhanced for reading? or a pdf but not based on the template on the site? by the way, I found their template awful for the reviewing purpose.
Submit in the format they ask for, otherwise paper is likely to be rejected without being read. You won't be reviewing the paper, so don't worry about how awful you think it is.

It's all here: tweb.acm.org/author.html including 


  Articles must follow the "Small Standard Format" described in the ACM formatting guidelines.