In this particular case, the answer is right there in the text. Signingorder.com is the website. Go there and look for a way to contact them. Gather all the information you can about them while you are there (company name, address, people, etc) then go onto google and look them up. Also, if you are on Facebook and a member of any of the larger notary groups, search for them in posts on Facebook.
That should give you enough information to know if you want to even work with them. It won't help you on this order, as, just like the earlier commenter said, it will be gone (someone else who is hungrier or less aware of their expenses than you will take it) before you can do research. It will help you to know about them when the next text comes in, especially if you put some notes in your phone's contact list about your research ("lowball" or "slow pay" or "good rep" works).
Bottom line is you need to do research on the companies who are seeking to use your services, especially those who text you out of the blue with no prior relationship with you at all. Just because you are on snapduds and they use that platform, that does not mean they are a good quality company that deserves to have you extend them credit (which is what working now and getting paid later amounts to).