To connect a projector to a video source, you obviously need to match the projector’s inputs with the source’s outputs. But given a choice, a digital connection is preferable to an analog connection.  Almost all current projectors include at least one HDMI port, which is the preferred choice for video sources and many computers, unless you plan to connect over a wired or wireless network. Many projectors still offer a VGA (analog) connector for computers and component video, but few new computers have VGA output ports, and few new video sources offer component video. Keep in mind that the HDMI version matters. Later versions support higher resolutions and more features than earlier versions. Make sure the HDMI version on the projector will let you take full advantage of the image sources you want to use, either by confirming it has the same HDMI version number as the image sources or that the manufacturer says it supports those specific features. You should also check the High-Bandwidth Digital Content Protection (HDCP) level. Virtually all 4K UHD HDR movies, for example, require HDCP 2.2 on both the player and the projector.  Note that some projectors' HDMI ports support Mobile High-Definition Link (MHL), which lets you project from older Android devices. This is becoming less common, however, since most newer Android devices can connect directly to an HDMI port via a USB-C-to-HDMI cable. A more useful extra today is that many current projectors support eARC on one of their HDMI ports, for connecting to an external audio system. Many models also have Wi-Fi connectivity built-in or can provide it through an included or separately purchased wireless dongle that plugs into a USB or HDMI port. Many support projecting directly from USB memory or memory cards.  A growing number of projectors include internet streaming features, either built-in or through an included streaming HDMI dongle. You can also buy third-party dongles to add streaming to virtually any projector with an HDMI port. Some models, most often portables, offer USB-C ports, which can (but don't always) support DisplayPort and HDMI protocols. Here also, check before buying to make sure you know what video support—if any—the USB-C connector offers.