There are really 2 things to consider;
a) what would happen if you were incapacitated in hospital for a number of days/weeks. (hopefully not you and your DH/DP at the same time), but are there any items that will have to be paid, or dealt with?
b) If you were to succomb to the virus and die.
You said you had not made a will, and do not state whether you are married to your DP or not, as the intestacy laws are different.
Keep a record of your usernames and passwords for your computer, laptop, phone, kindle, etc
You will have many other usernames and passwords for various sites, but you may be using a password manager for this.
Also, know where your house and car insurance, life assurance, etc is kept.
Keep a record of all your bank accounts (not on line bank details, but name of bank, account number, etc). You can keep this in a sealed envelope, etc. If you were to die, no one should be touching your bank account until probate is given, but if you have several accounts, shares, etc, it is helpful if someone was able to track them down.
(I did this last year, and gave a copy to my DS. He lives elsewhere, so if there are any burglaries in the house, it won't mean anything)
Obviously if you are working (whether from home, or elsewhere), your job would need to know. Are there any benefits to be paid from your job?
As your children are very young, I would keep a record of their daily routine. If you are the main carer, this would be helpful if either of you are in hospital.