Portal Systems?

Hello,
I am new here and could use some advise please. I have researched online for days and can't seem to find what I am looking for.
We are a construction/property maintenance company. We have some employees, but use a lot of outside sub-contractors too.
Right now, we receive a work order or requests from our customers and we email our vendors the information. We try to keep track using google drive for each job. Costs, dates due etc. I am constantly following up with the vendors. Calling and emailing trying to get an update on the job so I can make our deadlines.
Once complete, the vendor sends us their invoice and we invoice the customer. We have various relationships with the vendors. Some work on commission, some price the job and we mark it up, some are given an NTE. Right now our system is worked on manually (primarily me doing all the work) and relying on emails with communication info from the vendors/employees. There is much room for error. Some of our regular subs and employees have our company credit cards and access to our supply houses. Again, I try to keep track, but too much room for error.
I am looking for something to eliminate many of these issues. I don't think anything exists to do it all-Or maybe it does?
Portal systems are what some of our larger customers use for their vendors. (Our company being one of those)
Based on the above information, I need something to help me keep track of costs for each job, a vendor work order system where they have to sign in, update and even invoice from the portal.
I hope this makes sense. Thanks in advance for any help.