The developer of PowerPoint, Microsoft, does not provide users with a portable version, that is, one that does not require installation and can be run from a memory stick or external hard drive. Obviously, this statement is true if we keep to the use of official software. There is always the possibility that some portals offer such a version, although it is most likely fraud or a malicious application.
One point that sets PowerPoint apart from the portable version is that it comes integrated into a complete office suite, called Microsoft Office. To use this software package, a Microsoft 365 subscription is required, which must be paid on a monthly or annual basis. The advantage of this option is that it lets you update PowerPoint indefinitely. There is also the possibility of purchasing a license, gaining access to the latest edition of the application, namely Microsoft Office 2019. Both methods will let you use all the applications in the suite. Thus, it is not possible to obtain a single copy of PowerPoint, let alone one that does not require installation.
If you are looking for a portable alternative to PowerPoint, Malavida recommends several. First, Microsoft Office in its online version. The only requirement, in this case, is that you have an Internet connection on the computer you are using. With a similar operation, Google Docs can also become your ally if you are looking for presentation software that does not require installation. Also, both OpenOffice and LibreOffice have a secure portable version that you can run from any external device.
Do not forget that Microsoft Office is also free in other cases, especially those that have to do with mobility. Therefore, if your goal is to use it anywhere, you can count on its mobile and tablet apps for Android and iOS. These work without limitations, as long as your device is less than 10 inches. You only need to sign in with a Microsoft account.