With OLAT you can provide content in different forms. Except for the Wiki, which uses the JAMWiki syntax, all of the integrated text functionality is based on a WYSIWG HTML editor (TinyMCE). This gives you the entire scope of layout options: text formatting, tables and formulas as well as image and video implementation.
You want to import existing content? This is possible with an OLAT Course, or the two well established learning-content standards: CP and SCORM. Both are a collection of standards and specifications for web-based e-learning. OLAT currently supports IMS CP version 1.1.2 and SCORM 1.2, but not the SCORM version of 2004.
Additionally, OLAT has implemented the "IMS Question and Test Interoperability specification" (QTI). This defines a standard format for the representation of assessment content and results. So you can easily create and author the content outside of OLAT and use the assessment also with other delivery systems, repositories and learning management systems.
If you want to integrate an external learning applications into your course, you can do this by using of the course element LTI page. LTI means "Learning Tool Interoperability" and is an IMS standard to embed external learning applications such as a chat, media Wiki, test editor or a virtual lab.