Work out what you have to leave. Generally split between money, pensions, personal possessions and property.
Then decide who you want to leave it to, e.g. each other or DCs in equal shares.
If one of you dies, how will the other be supported in old age?
If Dcs, at what age should they receive inheritance, should you die first - 18, 21, 25 etc. I've left mine to ds to receive when he is 25, ie after university and about the time he might need a house deposit. But I don't have a partner to provide for.
Also, who will look after the dcs if you both die before they are adult? This is essential. Parents? Sibling? Friends? Get it agreed and written up.
If I die before my ds is adult, my sister will care for him. I have trustees (my brothers) to look after the money and pay for his maintenance until he is 21, then he gets whatever is left at 25. That means sis will receive money to pay for food, clothes, accommodation, his uni costs and so on.
Because your assets are a company, you might need to take advice. Could the company be sold or just asset disposal?
If you have a private pension, make sure someone is named as the beneficiary with the pension company. If this is done and you die before taking any pension, your beneficiary should receive the pension pot, without paying any tax.
Once you've thought of all these things, call some solicitors and get quotes for will writing. They will usually send you a form to fill in with all these details.