You would use Ultralight to interact with the Portal Network. This gives access to Ethereum data with very low CPU and memory requirements and near instant sync.
Ultralight is still in active developmenmt - it is not ready for production use!
You can download Ultralight from the project Github (opens in a new tab).
You can read the notes in the Github README (opens in a new tab)!
There you will find instructions for installing, running and interacting with Ultralight for your operating system.