PED Disclose Query for health insurance

Hi,

My age is 31. I am planning to buy health insurance for me, spouse and a kid.

I have two pre existing health conditions to disclose.

1. Sinusitis - I was operated because if sinus problem at the age of 15, 16 and 17 and again at the age of 23, unfortunately I dont have old reports with me. Last operation was 8 years ago and since then I didn’t face the issue again.
2. 6 months ago, I was diagnosed with Ulcer and admitted in hospital and discharged within 4 days. No operation was done, cured with few medications. Later after 3 months when I went for colonoscopy they said ulcer was completely cured. I have all the reports with me for this case.

How can I disclose above two conditions, as for the first case I dont have any reports. For the 2nd case since ulcer is completely cured now do I need to still disclose it? What is the impact if I didnt disclose?