When you have already made a job portal with a certain number of postings, you can also start collecting job postings from your users. All you need is to create a job submission form and link it to your Airtable base with job records to start collecting submissions there.
You can use one of the form layouts available on Softr (e.g. “Sales Form”) and configure its fields to correspond to your Airtable base with job records. Your form will eventually look something like the one shown below.