Investing for adult children

I have been investing in my daughter's JISA and Junior Sipp for several years within the tax allowance limit. Now she has turned 18, my wife and I wish to continue to contribute, usually monthly, in each of her investments without incurring any tax implications, namely IHT. Are we correct to think that these contributions could form part of our "normal expenditure out of income" if within the excess income from salaries (not savings) without affecting our gift allowance? Many thanks for your help.

Hi,
You can see guidance on inheritance tax here:
How Inheritance Tax works: thresholds, rules and allowances
Thank you.