How can I save videos from iCloud Drive or Google Drive to photos on my iPhone?

in the past I’ve been able to click a video in iCloud drive, and the option to ‘save to camera roll’ has been there. From there, I can use the instagram app and it will find the video stored in my photos/videos on the phone.

Now this option isn’t there. I can’t find a way to save the mp4 files to my phone at all. It’s not a huge file (35MB) but sending it to myself by email hasn’t worked.

Clicking 'open with instagram’ on the video in iCloud Drive does nothing, the menu goes away but it doesn’t open. If I click ‘open with winzip’ it will open in that app and allow me to play, but again gives me no option to save.

I managed this two weeks ago several times and it let me save it. What can I do???

I use this method for Google Drive, I think it's OK for iCloud Drive. Touch the three vertical dots and there will be the "Send a copy" option; Now, as you will see, there will be "Save Video", it will start exporting and your video will be saved in the roll

Change of basis when the basis aren't square

Finding the inverse of a symmetric $28\times28$ matrix

Maximum problem for heat equation

Let $A \subset \Bbb R^n$ be measurable and $B \subset \Bbb R^n$ such that $m^*(B)=0$. Show using the definition that $A \cup B$ is a measurable set.

If $\det(\mathrm{adj}\,A) \ne 0$, then $\det(A) \ne 0$.

Are there any two real nonzero numbers $a$ and $b$ such that $a^2+ab+b^2 = 0$ Why or why not?

What is the correct way of writing a vector element?

Are there any functions that are (always) continuous yet not differentiable? Or vice-versa?

Smallest Euclidean norm after matrix multiplication

Least prime divisor of $n!-1$ forms divergent series.

Example of a non-Lipschitz $f \in \mathrm{C}^1(U)$ where $U \subseteq \mathbb{R}^n$ is a non-convex compact connected set

What doe the term 'object' in the definition of a set mean?