Not sure if someone else has asked this question or suggested this before, but would be great to just add tasks "Today", without first having to add it to a project. From there then you can add it to a project, if the task does not get done that day. Because many times I just want to add things to get done today and if I don't get it done, I can either move it to tomorrow or to a particular project. Out of all the planner applications I have tried so far I like yours the best and would be willing to pay for a premium account if a few features were added. The other being that the tasks that don't get done today, get an option to be transferred to tomorrow, without having to manually do each one. Thanks for your help.
Unfortunately, no task in Todoist can exist outside of any project. However, there's a default "Inbox" project and you can put any task that doesn't necessarily "belong" to a project there.
As for your other request - you can multi-select tasks by clicking on them while holding the CTRL key and then choose the "postpone" option from the menu that will show at the top. We always recommend not to postpone tasks and leave them overdue as this way they will seem to be of higher priority. Please check our blog post with 3 great tips how this can increase your productivity: https://todoist.com/blog/2013/06/3-ways-to-drastically-improve-your-productivity/