Hi @SamanthaBr5 , there's an important distinction worth clarifying here that affects what's possible.
Issues (requests) don't have a portfolio of their own, portfolios belong to projects. While an item is still an issue sitting in a request queue, there's no portfolio relationship to reference yet, so a calculated field on the issue can't pull "the portfolio" because one doesn't exist at that stage. The portfolio only comes into play once the issue is converted to a project and a portfolio is assigned to that project.
So the honest answer is that auto-populating the actual portfolio on the intake form before conversion isn't possible natively, because the data simply isn't there yet.
A few paths depending on what you're trying to achieve:
If your requesters know which portfolio the work belongs to, you can add a dropdown or typeahead field on the intake form where they select it. That value stays on the object through conversion and can then be used to drive the project's portfolio assignment.
If you want the portfolio assigned automatically at conversion, the cleanest native route is request queue topics or routing rules tied to templates, each template can define a specific portfolio and program, so when the issue converts using that template, the project lands in the right portfolio without anyone manually setting it.
Once it's a project, pulling the portfolio name into a calculated field or report is straightforward, since the relationship exists at that point.
If your goal is truly to have the portfolio flow dynamically from the request without a template or manual selection, that's where Fusion becomes necessary which I know you're hoping to avoid, but it's the only way to bridge that gap natively-plus given issues have no portfolio field.