Short answer is mostly no. Long answer is nuanced, and depends on whether you are asking about the score or intelligence

Changing the “IQ score” (I am assuming a genuine test like WAIS-V, or at least something highly g-loaded like the old SAT):

• You can practice for them. This is actually a bad thing: IQ test is meant as a diagnostic tool, so practice effects make IQ tests less valid. I know most neuropsychs will discourage you from practicing the exam or taking the same test within 2~5 years after taking one
• Childhood IQ tests are somewhat less accurate than their adult counterparts, so sometimes two officially administered psych tests issued at two timepoints can differ by a lot.
• Some people have wildly differing scores on different subsections, quite common among Autistic people I believe. This defeats the whole premise of IQ itself and you will likely never get a very accurate aggregate estimate… but that does mean your score will change based on which test you take. For example, if you are a genius at quantitative reasoning (math intuition) but below-average at say processing speed, you’ll score much higher on old SAT or AGCT (where math is 1/3, no processing speed section) versus WAIS-V (which has no math sections, but does have processing speed)

Changing “intelligence” itself. This mostly never changes. However, if you have external factors that clog your mental, removing them do indeed improve intelligence:

• The single best way is to have good early childhood nutrition. This obviously can’t be changed…
• Have good nutrition and good sleep, and not take substances (alcohol, tobacco, drugs, etc…)
• Resolve ongoing mental disorders. It is well-known that depression drops IQ by quite a bit, for example

IQ has some white supremacist roots, so discussing about it is usually frowned upon… and even when used correctly, it is honestly much better used as a diagnostic tool. For example ADHD can get flagged on IQ tests very easily.

Personally I think instead of trying to improve per-se, it is much better used as a tool for self-discovery especially if you have any weird neurological conditions. If you’re worried about accuracy, there are old-SAT, CORE, CAIT, AGCT (the one US Army used to use)… which are all essentially IQ tests.