Annotation in 3D user interfaces such as Augmented Reality (AR) and Virtual Reality (VR) is a challenging and promising area; however, there are not currently surveys reviewing these contributions. In order to provide a survey of annotations for Extended Reality (XR) environments, we conducted a structured literature review of papers that used annotation in their AR/VR systems from the period between 2001 and 2021. Our literature review process consists of several filtering steps which resulted in 103 XR publications with a focus on annotation. We classified these papers based on the display technologies, input devices, annotation types, target object under annotation, collaboration type, modalities, and collaborative technologies. A survey of annotation in XR is an invaluable resource for researchers and newcomers. Finally, we provide a database of the collected information for each reviewed paper. This information includes applications, the display technologies and its annotator, input devices, modalities, annotation types, interaction techniques, collaboration types, and tasks for each paper. This database provides a rapid access to collected data and gives users the ability to search or filter the required information. This survey provides a starting point for anyone interested in researching annotation in XR environments.