Your contribution limit is determined by the plan you are enrolled in. If you are enrolled in a family plan that covers your spouse, you are eligible to contribute up to the family limit. It is not necessary for your spouse to be enrolled in an HDHP.
However, it is important that you can’t have any other non-HDHP coverage. If your spouse’s insurance also covers you, then you are disqualified from making HSA contributions. (It’s OK for your spouse to have overlapping coverage from your plan and her own plan, but you must not have overlapping coverage from her plan on top of your own plan.)
Also, if your spouse participates in a flexible spending account (FSA) with her medical insurance, that also disqualifies you from contributing to an HSA. An FSA can be used to pay the medical expenses of the account holder, their spouse, or their dependents, so even if your spouse‘s medical coverage only includes herself, if she has an FSA, that covers you, and that counts as other coverage, which disqualifies you from contributing any amount to an HSA.
