Most models of iPad require a Power source rated at 12W (i.e., 2.4A @5V) or greater to reliably charge. 5W Power sources (1.0A @5V), commonly found in automotive and domestic furniture, are inadequate to charge an iPad; if the iPad charges at all, charging will be very slow. Recent models of iPad are supplied with a 20W USB-C Power Adapter.
Some third-party USB-C power outlets (and portable PowerBanks) may not support USB PD (Power Delivery). Power Delivery mutually negotiates the charging voltage; the source, load and cable are all elements involved in the negotiation protocol. Unless the USB-C Power source explicitly supports USB PD, it will almost certainly fail to charge the iPad; proprietary charging standards, such as QC (Quick Charge), are not supported. If using a USB Type-A power source, this will be a standard USB 5V supply - and will not be using USB PD to supply power to the connected iPad.
If you experience difficulties when using an appropriate Power source of 12W or greater, you might be best advised to seek assistance from the manufacturer and/or Apple Support. You can contact the Apple Support Team using the Support link at top-right or bottom-left of this page. Alternatively, you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:
https://apps.apple.com/app/apple-support/id1130498044