"Document" is a common generic catch-all for this and other cases that don't have a more specific item type. It's your database, so as long as you know what the item is that's all that really matters. If you want to add more refined sub-categorization that would allow you to easily retrieve such items you could assign a tag, or add it to a specific collection.
Unless of course you need to cite it in formal writing and there is a required standard format for doing that, which the word processor plugin would need to use. At which point Zotero developers might consider adding a new item type (but I understand that historically that has been rare).
Are you expecting to cite the proposal using a particular style guide? APA, Chicago, MLA? I did a quick glance at these resources but didn't find relevant guidance.
There are many things that could be called an "proposal". Are you asking about a request for applications/proposals document offering funding for a specified project from a government agency, foundation, or NGO? A proposal document responding to an RFA? A business proposal to a potential customer? A planning proposal? An academic (course) proposal? A formal philosophical proposal?
What are the essential elements you wish to cite? Offering entity? Responding entity? Some particular scope of work? The proposal's reference list?
What type of document will contain a citation to a proposal? What is the audience who will read your document that will contain a citation to a proposal?
The Zotero Report type probably has sufficient fields to include all relevant information about a proposal document but I have no idea what you must do with data entry so that what you get in-text and in the bibliography will meet your needs or desires without needing to perform edits to your final document.
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Unless of course you need to cite it in formal writing and there is a required standard format for doing that, which the word processor plugin would need to use. At which point Zotero developers might consider adding a new item type (but I understand that historically that has been rare).
There are many things that could be called an "proposal". Are you asking about a request for applications/proposals document offering funding for a specified project from a government agency, foundation, or NGO? A proposal document responding to an RFA? A business proposal to a potential customer? A planning proposal? An academic (course) proposal? A formal philosophical proposal?
What are the essential elements you wish to cite? Offering entity? Responding entity? Some particular scope of work? The proposal's reference list?
What type of document will contain a citation to a proposal? What is the audience who will read your document that will contain a citation to a proposal?
The Zotero Report type probably has sufficient fields to include all relevant information about a proposal document but I have no idea what you must do with data entry so that what you get in-text and in the bibliography will meet your needs or desires without needing to perform edits to your final document.