This page describes the ways you can edit items already saved in your Zotero Library.
By selecting an item in the center pane, you will then be able to view and edit all of its bibliographic information in the right pane, in the Info Tab as shown below:
To change a creator (such as an author or editor), click the Creator Field label and select the desired creator type.
You can add and delete creators by clicking on the plus (+) or minus (-) button at the end of each field, shown here:
Creators can be re-ordered by clicking the Creator Field Label and selecting "Move Up" or "Move Down." See here:
Journal Articles are sometimes cited with the abbreviated journal title. Zotero stores both titles in two separate fields:
You can edit these fields by selecting an item in the center pane, and editing the information in the right pane, shown here:
Please Note: Some citation styles require different abbreviations, usually based on whether or not the abbreviation includes periods (e.g., "PLoS Biol" vs. "PLoS Biol."). Zotero recommends storing abbreviated journal titles with periods, so that Zotero can remove the periods when using a specified citation style in an exported bibliography.
In English, titles are typically formatted in "Title Case" or "Sentence case".
(e.g., Effects of Treatment on Population)
(e.g., Effects of treatment on population)
APA Website explains title case formatting.
Different citation styles require different casing requirements, but Zotero recommends storing titles in your Zotero library in "Sentence case," as this is generally more accurate than the other style, and Zotero can easily and more reliable convert titles when the bibliographic citation style requires it.
The Extra field is used to store custom item metadata or data that doesn't have a dedicated field in Zotero.
As explained on their website, Zotero will import metadata from a webpages, bibliographic databases, library catalogs and publisher sites as accurately as possible, but the information may not always been fully correct or complete.
When using this software, you should understand the possibility of these issues and always verify the records in your library. Verify that your records have the correct information and formatting so that you can create accurate in-text and biblographic citations.