Depends on the type of tender. Some private companies send out a tender pack usually including a scope of work and they ask for pricing, H&S info, insurance etc. Some can be simple ... some more detailed. If it's a public tender they tend to be more in depth and look at no years established, turnover, experience etc and they will also likely require info on safety, quality, environmental and sustainability or CSR (Corporate Social Responsibility) aspects. An example, I have spent between 1-2 hours on a basic tender, but I have also recently spent over 30 hours work for a public tender (this was after spending 8-10 hours at pre-qual stage). Be prepared to put in a fair amount of work if you have to, particularly on large contracts.